Typically, a one-component stator is inexpensive and heavily used in standard inner rotor motors, but has limits in the winding process (copper wire diameter, filling factor, inner diameter, and the like) and as a consequence is limited in reaching high efficiency versus cost and package targets.
Two-component stator designs are known. Typically, a two-component stator consists of cutting a ring for a stator yoke and a separate cutting a star which, once separately wound, is then axially pressed into the rotor yoke. Such a stator construction may allow for improved winding with high copper diameter and filling factor but it generates several disadvantages, including (i) high and variable insertion forces required to press the star into the yoke, which makes the process difficult to control, (ii) the necessity to cut the two parts of the stator in different punching stations, in order to have a better dimensional control and for reducing the insertion force issues, which increases the part cost due to process labor and iron scrap, and (iii) iron losses generated by electrical contacts due to interference and not perfect alignment between yoke/star lamination (eddy currents in excess that downgrade the laminations grade).